Diesel exhaust fluid tank housing

ABSTRACT

This invention relates generally to diesel exhaust fluid tanks, commonly referred to as DEF tanks and more specifically to a housing to enclose the DEF tank, which in the preferred embodiment is insulated to protect the housing from both contaminants as well as extreme temperatures that could adversely effect the DEF mixture in the DEF tank.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/011,639 filed on Jun. 13. 2014.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to diesel exhaust fluid tanks, commonly referred to as DEF tanks and more specifically to a housing to enclose the DEF tank. In the preferred embodiment the housing is insulated to protect the DEF tank from both contaminants as well as extreme temperatures that could adversely affect the DEF mixture in the DEF tank.

2. Description of the Prior Art

Diesel Exhaust Fluid (DEF) tanks are well known for use with diesel engines. Diesel Exhaust Fluid (DEF) is an Aqueous Urea Solution made with 32.5% high-purity urea and 67.5% deionized water. DEF is used as a consumable in selective catalytic reduction (SCR) in order to lower NOx concentration in the diesel exhaust emissions from diesel engines.

Diesel engines can be run with a lean burn air-to-fuel ratio to ensure the full combustion of soot and to prevent the exhaust of fuel that has not been burned. The excess of oxygen necessarily leads to the generation of nitrogen oxides (NO_(x)), which are harmful pollutants. Selective catalytic reduction is used to reduce the amount of NO_(x) released into the atmosphere. Diesel exhaust fluid (from a separate DEF tank) is injected into the exhaust pipeline, the aqueous urea vaporizes and decomposes to form ammonia and carbon dioxide. Within the SCR catalyst, the NO_(x) are catalytically reduced by the ammonia (NH₃) into water (H₂O) and nitrogen (N₂), which are both harmless; and these are then released through the exhaust.

DEF is stored in a tank on board the vehicle, and injected into the exhaust stream by a metering system. The injection rate depends on the specific after-treatment system, but is typically 2-6% of diesel consumption volume. This low dosing rate ensures long fluid refill intervals and minimizes the tank's size (and subsequent obtrusion into vehicle packaging space). DEF pumps are typically provided at diesel refueling station, so that the vehicle operator can fill both without moving the truck.

An electronic unit adjusts the addition of fluid in accordance with such parameters as engine operating temperature and speed. Sensors are mounted in the tank to ensure that the DEF is at the correct mixture and temperature. In the event that the DEF is not correct, the sensors will send a signal to the engine electronics and de-rate the engine, or in other words, cause the engine to begin to lose power. De-rate is a stepped process, initially causing a loss of power which increases incrementally until the engine eventually stops operating.

The temperature of the DEF is critical to its effectiveness and use. If the temperature drops below 12° Fahrenheit the DEF will freeze and if the temperature exceeds 120° Fahrenheit the DEF will begin to degrade. If the DEF gets to temperatures above 150° to 180° biuret can be created. To control the temperature, DEF tanks have engine coolant circulating though lines or tubes in the tank. Sensors within the tank sense and a manifold on top of the tank controls the flow of coolant through lines or tubes in the tank to maintain a desired temperature in an appropriate range. However, the DEF directly adjacent the lines can experience temperatures high enough to create biuret. The biuret accumulates in the bottom of the tank and interferes with the sensors and can result in a de-rate of the engine. Another potential de-rate occurs from the accumulation of contaminants, such as dirt in the tank. The tank has a vent tube that sucks in ambient air as the DEF is pumped form the DEF tank. This vent tube draws in contaminants that can foul the sensors, again causing the engine to be de-rated.

As referenced above, another problem with DEF tanks is low temperatures. DEF can freeze. This is a common problem with vehicles that are used in cold climates and not operated for a period of time, such as over night. If the temperature is low enough and coolant is not being circulated through the lines in the tank, the DEF will freeze. When the vehicle is started after freezing of the DEF, the vehicle is de-rated, until the coolant circulating in the tank thaws the DEF so that it can be pumped. This creates downtown for the vehicle and the operator, generally around an hour.

SUMMARY OF THE INVENTION

The subject invention provides a DEF tank that solves the problem of contaminant and temperature problems found with existing DEF tanks. The present invention provides a housing that encapsulates the DEF tank to shield the tank from contaminants. This reduces fouling of the sensors and de-ratings of the tank. Additionally, the preferred embodiment includes insulation to further protect the tank from temperature changes, and electric heating elements, or pads that are electronically controlled. This reduces downtime, since the DEF does not freeze overnight. Additionally, in some applications, the use of coolant lines can be eliminated, reducing if not eliminating the problems associated with biuret production.

The invention is a diesel exhaust fluid system that has a housing with a main body that is open for the receipt of a tank containing diesel exhaust fluid. A cover is mounted to the front side to close the opening and virtually seal the DEF tank within the housing.

The housing and the cover have an interior wall and an exterior wall that are spaced from one another to define a gap. A layer of insulation is positioned in the gap between the interior wall and the exterior wall. The insulation protects the diesel exhaust fluid within the tank from extreme temperatures.

The DEF tank is positioned within the housing and fully enclosed within the housing and the cover. When that cover is attached, the housing and cover insulates the DEF tank from extreme temperatures and restricts the ingress of contaminants that could adversely affect the performance of the DEF tank.

The DEF tank includes a header assembly mounted to the tank for controlling the flow of the diesel exhaust fluid. The header assembly is mounted within the housing to protect the header from extreme temperatures as well as contaminates. The header includes electronics that are also protected.

The tank includes a vent tube that allows the tank to draw in air to prevent a vacuum from developing within the tank as diesel exhaust fluid is drawn from the tank. The housing includes a window and a filter mounted in the window to filter air before it enters the vent tube. The vent tube is positioned adjacent the filter so that it draws air through said filter.

The diesel exhaust fluid system also includes a mounting assembly. The mounting assembly includes a mounting member, which is the disclosed embodiment is a plate. The mounting assembly has a first set of fasteners to mount the mounting member to the tank. A second set of fasteners extends through the mounting member and the back of the housing and into a mount on a vehicle to secure the diesel exhaust fluid system to the vehicle. Due to the mounting system, the housing main body does not support the weight of the tank. The weight of the tank is supported by the mounting assembly, which is attached to the vehicle. The mount of the present invention is unique and provides a universal mount for vehicles of various types.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective exploded view of the diesel fluid exhaust system of the subject invention;

FIG. 2 is a perspective view of the housing main body and the tank of the subject invention;

FIG. 3 is a perspective view of the housing cover of the subject invention;

FIG. 4 is a perspective view of the housing main body of the subject invention;

FIG. 5 is a perspective view of the back of the main body of the subject invention;

FIG. 6 is a cutaway side view of the diesel fluid exhaust housing of the subject invention;

FIG. 7 is a perspective view of the DEF tank of the subject invention;

FIG. 8 is a cutaway side view of the diesel fluid exhaust housing of the subject invention; and

FIG. 9 is a perspective cutaway view of the DEF tank of the present invention.

DESCRIPTION OF THE ENABLING EMBODIMENT

With reference to FIGS. 1 through 5, the insulated DEF tank housing of the present invention is shown generally at 10. A molded DEF tank 15 is mounted within the housing 10. The housing 10 has a main body 12 and a removable cover 14. The main body 12 includes a top 16, opposed sides 18 and 20, a bottom 22 and a back 24. In the disclosed embodiment, the main body 12 is a single unitary piece that is rotary molded; however it will be appreciated by those of ordinary skill in the art that that the main body could be made in separate pieces and made by other forming methods, such as injection molding.

As disclosed, the cover 14 is also a unitary piece and is attached to the main body 12 with bolts or screws. However it will be appreciated by those of ordinary skill in the art that other attachment systems could be used, including, snaps, Velcro type fasteners, mating slides molded into the cover 14 and body 12, etc.

With reference to FIG. 6, the main body 12 and cover 14 have spaced exterior walls 30 and interior walls 32. Insulation 34 files the gap between the walls 30 and 32. In the disclosed embodiment, the insulation 34 is an expanded foam insulation that is pumped between the walls 30 and 32 once the body 12 and cover 14 are removed from the rotary mold cavity. However it will be appreciated by those of ordinary skill in the art that other forms of insulation could be used including Styrofoam insulation, fiberglass insulation, etc.

As is well known, the DEF tank 15 has to be regularly refilled. A refill neck and cap are shown at 36. The cover 14 has an opening 37 for receiving the neck and cap 36. The neck and cap 36 are the only portions of the DEF tank 15 that are not fully enclosed within the housing 10.

A window 38 in the back 24 of the body 12 provides an exit opening for the tubes 42 and 46. In the preferred embodiment, the window 38 includes a filter medium 44 to prevent the ingress of contaminants. The DEF tank 15 includes a vent tube 39 that draws in ambient air as the pump withdraws fluid from the tank 15. As will be appreciated, the filter medium filters contaminants from the vent tube 39.

The DEF tank 15 is disclosed as a rotary molded tank for containing the DEF solution. As illustrated, the DEF tank 15 includes a header assembly 40. The header assembly contains a heating system 41 that includes exterior tubes 42 and interior tubes 44. The exterior tubes 42 are connected to the engine coolant system of the vehicle and circulates heated water through the interior tubes 44. The circulated water through the interior tubes 44 maintains the DEF mixture within the DEF tank at the desired temperature while the vehicle is running.

Additionally, a separate heating element 47 can be positioned adjacent the DEF tank 15 to provide additional heating. The heating element 47 would be electronically controlled to apply additional heat when needed. Only one element 47 is illustrated, but it should be appreciated that two or more could be used if desired.

The heating element 47 can be either 12 volt or 120 volt and can be engaged in cold environments to prevent the DEF from freezing if the vehicle is not going to be used for an extended period of time.

A discharge tube 46 and suction line 48 are provided in the header assembly 40 to supply the DEF mixture to the DEF pump and injectors.

Electrical connections 50 are provided for supplying power to the sensors 52 and connections to the computer processor (not shown) as well as power to the heating element 47. The sensors 52 sense the level of the DEF fluid and the fluid mixture to ensure that the correct amount and mixture is being supplied to the ejectors. In the event either the mixture composition is outside of acceptable parameters, or the level is to low or the temperature is to low, the computer processor will signal a shutdown of the header, which in turn effects the operation of the vehicle.

With reference to FIGS. 1 and 9, the disclosed mounting system is generally illustrated at 70. The mounting system 70 includes a mounting member 72, which as disclosed as first and second plates 73 and 75. The member 72 could also be strips of on each side of protrusion 74. In the disclosed embodiment, the member 72 is made of metal. However it will be appreciated by those of ordinary skill in the art that the member 72 is not limited to the disclosed shapes and could take various shapes depending upon the configuration of the DEF tank to which it is mounted and could be made of different material, such as for example aluminum, steel, carbon fiber, fiberglass, etc.

As disclosed, the plate 73 of member 72 is mounted to the DEF tank 15 by bolts 76 or screws. The tank 15 in the disclosed embodiment has nuts molded into the tank wall to receive the bolts 76. However it will be appreciated by those of ordinary skill in the art that other fasteners could be used, including screws, plastic bosses to receive either bolts or screws, etc.

The plate 73 of member 72 has holes 78 for receipts or bolts 80. The bolts 80 extend through the holes 78 and through mating holes 82 in the back 24 and then into holes 83 in plate 75. The bolts 80 extend through the plate 75 and into the mounting bracket 77 on the vehicle. A nut 77 (not shown) is threaded onto each bolt 80 to sandwich the back 24 between the member 72 and the mounting bracket 77. Due to the surface area of the member 72 and the compression of the back 24 between the member plates 73 and 75 and the bracket 77 the housing 10 supports the majority of the weight of the housing 10 and the DEF tank 15. The connection of the DEF tank 15 to the plate 73 of mounting member 72 only holds the tank 15 within the housing 10 to prevent it form moving. The bolts 76 see very little weight and merely retain the tank 15 in relationship to the housing 10.

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. These antecedent recitations should be interpreted to cover any combination in which the inventive novelty exercises its utility. The use of the word “said” in the apparatus claims refers to an antecedent that is a positive recitation meant to be included in the coverage of the claims whereas the word “the” precedes a word not meant to be included in the coverage of the claims. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting. 

What is claimed is:
 1. A diesel exhaust fluid system comprising: a housing having a main body, the main body having a back side and a front side to define an opening for receipt of a tank containing diesel exhaust fluid; a cover mounted to said front side to close said opening; said housing and said cover having an interior wall and an exterior wall, said interior wall and said exterior wall being spaced from one another to define a gap; a layer of insulation positioned in said gap between said interior wall and said exterior wall; a tank for containing diesel exhaust fluid; said tank being positioned within said housing and fully enclosed within said housing and said cover; whereby said housing and cover insulates said tank from extreme temperatures and restricts the ingress of contaminants.
 2. The diesel exhaust fluid system of claim 1, wherein said tank includes a header assembly mounted to said tank for controlling the flow of diesel exhaust fluid, said header assembly being mounted within said housing; whereby said housing and cover insulates said header assembly from extreme temperatures and restricts the ingress of contaminants.
 3. The diesel exhaust fluid system of claim 1, wherein said tank includes a refill neck and cap, said neck extending through said housing and cover, said cap being positioned outside said housing and cover such that said tank can be refilled with diesel exhaust fluid.
 4. The diesel exhaust fluid system of claim 1, wherein said tank includes a vent tube.
 5. The diesel exhaust fluid system of claim 4, wherein said housing includes a window and a filter, said vent tube being positioned to draw air through said filter.
 6. The diesel exhaust fluid system of claim 1, including a mounting assembly, said mounting assembly including a mounting member, said mounting assembly including a first set of fasteners to mount the mounting member to said tank and a second set of fasteners extending through said mounting member and said back of said housing and into a mount on a vehicle to secure the diesel exhaust fluid system to said vehicle; whereby said housing main body does not support the weight of said tank.
 7. The diesel exhaust fluid system of claim 6, wherein said mounting member includes a first plate attached to said tank and a second plate positioned against said housing, said first and second plates sandwiching said housing between said plates.
 8. The diesel exhaust fluid system of claim 6, wherein said mounting member is a plate.
 9. The diesel exhaust fluid system of claim 1, wherein said tank includes tubing that extends into said tank to circulate coolant through the tank.
 10. The diesel exhaust fluid system of claim 1, further including a heating element positioned adjacent said tank.
 11. The diesel exhaust fluid system of claim 1, wherein said tank includes sensors to sense quality of the fluid, depth of the fluid and temperature of the fluid.
 12. A diesel exhaust fluid system housing, said housing comprising: a main body, the main body having a back side and a front side to define an opening for receipt of a tank containing diesel exhaust fluid; a cover generally mounted to said housing to close said opening; said housing and said cover having an interior wall and an exterior wall, said interior wall and said exterior wall being spaced from one another to define a gap; a layer of insulation positioned in said gap between said interior wall and said exterior wall; whereby said housing and cover insulates a diesel exhaust fluid tank from extreme temperatures and restricts the ingress of contaminants into the tank.
 13. The diesel exhaust fluid system housing of claim 12, wherein said housing includes a space to receive a header assembly mounted to a tank for containing diesel exhaust fluid, said header assembly being adapted to be positioned within said space in said housing; whereby said housing and cover insulates said header assembly from extreme temperatures and restricts the ingress of contaminants.
 14. The diesel exhaust fluid system housing of claim 12, wherein said housing includes a window and a filter.
 15. The diesel exhaust fluid system housing of claim 12, further including a mounting assembly, said mounting assembly including a mounting member, said mounting assembly including a first set of fasteners to mount the mounting member to a tank and a second set of fasteners extending through said mounting member and said back of said housing and into a mount on a vehicle to secure the diesel exhaust fluid system to said vehicle.
 16. The diesel exhaust fluid system housing of claim 15, wherein said mounting member is a plate.
 17. The diesel exhaust fluid system of claim 15, wherein said mounting member includes a first and second plate.
 18. The diesel exhaust fluid system of claim 17, wherein said first and second plates sandwich said housing between said first and second plates.
 19. The diesel exhaust fluid system of claim 12, further including a heating element positioned adjacent said tank. 